How to measure aluminium doors: Getting the opening size right is the most important step before you order an aluminium door — and doors need a few checks that windows do not, including the door type, the floor threshold and the opening direction. This guide walks through exactly how to measure for an aluminium sliding, hinged, pivot or folding door before you order, with a checklist and the mistakes we see most often.
How to measure aluminium doors, step by step
Getting the size right is the most important part of ordering. This guide on how to measure aluminium doors takes you through measuring the structural opening accurately, allowing for the frame and any tolerances. Follow these how to measure aluminium doors steps and you will order a door that fits first time, whether it is a sliding, folding or hinged door.
Key takeaways: how to measure aluminium doors
- Measure the structural (brick) opening — width and height — not the old frame.
- What you measure depends on the door type: sliding, hinged/pivot or folding/stacking.
- For hinged and pivot doors, record the opening direction (in or out) and handing.
- Coetz™ supplies standard sizes made to order — pick the size that fits your opening with a fitting clearance, and confirm before you order.
Why measuring a door is different from a window
A door reaches the floor, so the threshold and floor finish matter — measure to the finished floor level, not the raw slab. Doors also come in very different operating styles, and each is measured slightly differently. And unlike a window, a swing door has an opening direction and handing that you must specify.
Tools you need: how to measure aluminium doors
- A steel tape measure (not a fabric one)
- A pen and paper, or your phone, to record every figure
- A spirit level to check the opening is square
- A helper for wide sliding and stacking openings
Step 1: Measure the width: how to measure aluminium doors
Measure the width of the structural opening in three places — top, middle and bottom — and record the smallest figure. Openings are rarely perfectly square, and the door must fit the tightest point.
Step 2: Measure the height: how to measure aluminium doors
Measure from the finished floor level up to the underside of the lintel on the left, centre and right, and record the smallest figure. If the floor is not yet tiled or screeded, allow for the final finish so the door is not left too high or too low at the threshold.
Step 3: Opening direction and handing (hinged & pivot)
For hinged and pivot doors, decide whether the door should open inward or outward, and note the handing — which side the hinges sit on. Because handing conventions vary, describe it in plain language, for example: “hinged on the left, opening outward, viewed from outside.” Sliding, folding and stacking doors do not open in or out — instead, note the stacking direction (which side the panels gather).
Measuring by door type: how to measure aluminium doors
| Door type | What to measure | Key note |
|---|---|---|
| Sliding & patio | Full opening width and height | Specify which panel slides |
| Hinged & pivot | Opening width and height | Record open-in/out and handing |
| Folding & stacking | Full opening width and height | Record number of panels and stacking side |
Structural opening vs frame size: how to measure aluminium doors
The figures you record are the opening size. The aluminium frame is made slightly smaller so it fits into the opening with a fitting clearance for packing, levelling and sealing. When you order a standard Coetz™ size, choose the size that fits your measured opening — if you are between sizes, go down, never up.
Common measuring mistakes: how to measure aluminium doors
- Measuring the old frame instead of the structural opening
- Measuring height from a raw slab instead of the finished floor
- Measuring only once instead of in three places
- Forgetting to record the opening direction and handing
- Rounding up to a bigger size that will not fit
Measurement checklist: how to measure aluminium doors
- Width measured top, middle and bottom — smallest recorded
- Height measured left, centre and right from finished floor — smallest recorded
- Door type chosen (sliding, hinged/pivot, folding/stacking)
- Opening direction and handing noted (swing doors)
- Threshold and floor finish allowed for
- Sizes double-checked before ordering
When to ask for help: how to measure aluminium doors
If your opening does not match a standard size, is out of square, or you are unsure of the handing, contact the Coetz™ team or send a photo on WhatsApp before ordering. We are glad to help you choose the right size — but final responsibility for measurements remains with the customer.
Frequently asked questions
Do I measure the brick opening or the door frame?
Measure the structural (brick) opening — width and height. The aluminium frame is manufactured slightly smaller so it fits into the opening with a fitting clearance. Always confirm your sizes before ordering, as Coetz cannot be responsible for incorrect customer measurements.
What is the difference between open-in and open-out?
A hinged or pivot door can be set to open inward or outward. Choose based on the space available and how the door is used. It affects which side the hinges and handle sit, so note it clearly when you order.
How do I describe the handing of a door?
Handing describes which side the door is hinged and which way it opens. Because conventions vary, note it in plain language — for example ‘hinged on the left, opening outward, viewed from outside’ — and confirm it with our team.
Do sliding doors need an opening direction?
Sliding and stacking doors run along a track rather than swinging, so there is no open-in or open-out. Instead, specify which panel slides and the stacking direction (which side the panels gather).
Can Coetz confirm my door measurements before I order?
Yes — send your opening sizes and a photo via the contact page or WhatsApp and our team will help you choose the right standard size. Final responsibility for measurements remains with the customer.
Related
Ready to order? Browse aluminium doors, patio sliding doors and stacking doors. Also see how to measure aluminium windows and our guide to safety glass.
How to measure aluminium doors: a practical checklist
Clients ask us, How to measure aluminium doors? The honest answer depends on the opening, the traffic through it and what the building already has in place, so the checklist below is what our estimators actually work through.
- The structural opening. Measure the brickwork opening rather than an existing frame, and check the reveal is square and plumb.
- Configuration. Confirm the opening arrangement, which panes open, and which way they open before anything is manufactured.
- Colour. Five finishes are stocked — black, white, bronze, charcoal and natural anodised — and some carry a premium.
- Glass. Coetz™ glazes as standard with 6.38 mm clear laminated safety glass.
- Supply only. Aluminium windows and doors are supplied, not installed, so allow for your own installer.
If that question applies to one specific opening on your project, send us the sizes and a photo of the existing entrance. That is normally enough for us to answer it, and to quote, without a site visit.
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